The billionaire known as "China's Warren Buffett" has resurfaced after briefly disappearing last week, but his presence failed to reassure investors in Fosun Group. The conglomerate's shares dived more than 10% when trading resumed Monday, and Chairman Guo Guangchang appeared in public at a corporate meeting, the Wall Street Journal reports. After he couldn't be contacted on Friday, the company said he was "currently assisting in certain investigations carried out by mainland judiciary authorities," which many took to mean that he had been caught up in Beijing's ongoing crackdown on corruption, the AP reports. He made no mention of the investigation during his remarks Monday, and uncertainty continues to surround the company, the Journal notes. (More China stories.)